This is the most important painting by Lerolle, a friend and collector of such artists as Degas, Denis, and Vuillard. Set in the choir loft of the church of Saint-François-Xavier in Paris, it features members of Lerolle’s intimate circle, including his wife (bare-headed) and her sisters, in fashionable matching hats; his brother-in-law, composer Ernest Chausson, plays the organ. The painter himself gazes outward at left. Shown at the Salon of 1885, this picture triumphed the next year in New York, in the first major Impressionism exhibition in America. One critic recalled, "spectators … spoke low before it, as if waiting for … the voice of the singer to be heard."
(http://www.metmuseum.org/art/collection/search/436880)